Technical Field
The present invention relates to a cryogenic refrigerator that has a displacer.
Description of the Related Art
In the related art, a Gifford McMahon refrigerator (hereinafter referred to as GM refrigerator) is known as a cryogenic refrigerator including a displacer. The GM refrigerator is configured so that the displacer reciprocally moves within a cylinder by a drive unit.
Additionally, an expansion space is formed between the cylinder and the displacer. A pressurized refrigerant gas supplied from a compressor expands in the expansion space and is returned to the compressor to thereby generate cryogenic refrigeration.
Additionally, a GM refrigerator having a configuration in which a spool valve performs switching between the supply and return of a refrigerant gas is also suggested in the related art.